Cockroach Identifier: Which Roach Do You Have?

• German cockroach: identified by small size plus two dark parallel lines running from the back of the head to the wings.
• Oriental cockroach: adults are very dark brown to nearly black with a somewhat greasy body sheen.
• Wood cockroaches are smaller/lighter than American cockroaches (which are larger, reddish-brown) and lighter-colored than Oriental cockroaches (dark brown to nearly black).
• Cockroaches are sometimes confused with beetles, but cockroaches have membranous wings and lack beetles' thick, hardened forewings.
• Termites are taxonomically close to cockroaches (both classified under Dictyoptera), which is why the two are sometimes conflated.
• Pennsylvania wood cockroaches are not pests outdoors — they are ecosystem indicators/decomposers, unlike household pest species.

People most often mix cockroaches up with:

• Termites
• Beetles

Open the other page and compare its list against the marks above; the differences are usually in the antennae, wings or the way the body is divided.

Sources do not describe cockroaches biting or stinging humans; they do describe cockroach excrement and cast skins as containing allergens that commonly cause allergic reactions. Seek medical care promptly for severe symptoms or any allergic reaction.

Cockroaches are described as among the most important household and public-health pests, given their disease-transmission and allergen risks.

Cockroaches hide by day in warm, dark, moist areas such as cracks, water meter boxes, sewers, and crawl spaces, coming out at night to feed; the German cockroach is the most common indoor species, especially in multi-unit housing.

Get as close as your camera will focus, from directly above, in daylight or a bright lamp. Include the whole body with the legs and antennae in frame; a second shot from the side shows wings and body segments. Put a coin or ruler next to it for scale. For a bite or a bug found on skin or bedding, photograph the bug itself, not the mark. The app names the likely group; use the list above to confirm.

You tell which cockroach you have from its size, its colour, the marks behind its head and where in the house it turns up. These are the four species US extension services describe most:

• German cockroach: 1/2 to 5/8 inch, tan to light brown, with two dark parallel lines running from the back of the head toward the wings (Penn State). Kitchens and bathrooms, near dishwashers, stoves and sinks. The female carries her purse-shaped egg capsule, which holds up to 48 eggs, sticking out of her abdomen until it hatches.
• Brownbanded cockroach: about 1/2 inch, with distinct yellow bands across the wings (University of Nebraska-Lincoln). Prefers warmer spots higher up and away from water, such as cabinets, closet shelves, behind pictures and near refrigerator motors.
• Oriental cockroach: about 1 to 1 1/4 inches, dark brown to black with a greasy sheen; males have wings shorter than the abdomen and females only stubs (UNL). Basements, floor drains and crawl spaces; University of Minnesota Extension notes it tolerates cool conditions and has been found outdoors in freezing weather.
• American cockroach: about 1 1/2 inches (UNL) and up to 2 inches (UC IPM), reddish-brown, with long wings covering the abdomen. Boiler rooms, steam tunnels, basements, around pipes and in floor drains.

Young cockroaches (nymphs) look like smaller, wingless adults, which is why a small, wingless roach is not necessarily a different species.

University of Minnesota Extension names long-horned beetles, crickets, leaf-footed bugs and ground beetles as insects that resemble cockroaches. The two most common mix-ups have simple tests:

• Ground beetles: shiny and dark like an Oriental cockroach, but with hardened front wings (wing covers), where a cockroach has leathery wings or none. University of Kentucky entomologists add that cockroaches have a hood-like plate that hides the head when seen from above. Ground beetles wander in occasionally, do not stay indoors, and are beneficial predators.
• Giant water bugs: 2 to 4 inches, with pincer-like front legs for grabbing prey and oar-like hind legs for swimming; they live in ponds, marshes and slow streams and can give a painful bite (Orkin). A cockroach has neither the pincers nor the paddles.
• Crickets: long jumping hind legs; see grasshoppers, crickets and katydids.
• Other beetles: any hard, shell-like wing covers mean a beetle, not a roach.

Several everyday names are cockroaches under another label:

• Palmetto bug: the American cockroach (Orkin).
• Waterbug: often the Oriental cockroach, which is not aquatic despite the name; it lives in damp sewers, basements, cellars and crawl spaces (Orkin). A true water bug lives in ponds and streams.
• House roach: not a species. People use it for whatever cockroach lives indoors, and in most homes that is the German cockroach, which University of Minnesota Extension and UC IPM describe as the most common indoor species.

Squashing a cockroach smears what it carries onto the surface. Penn State Extension reports that disease-causing bacteria, protozoa and viruses have been found on cockroach bodies, and that cockroach droppings and cast skins contain allergens that cause skin rashes, watery eyes, sneezing, nasal congestion and asthma. UC IPM adds that cockroach allergens are a risk factor for asthma in children.

The cleaner approach, from UC IPM, is to vacuum cockroaches and their debris, ideally with a vacuum that has a HEPA or triple filter, keep food in insect-proof containers and bins tightly lidded, and use sticky traps to see which species you have and where they are coming from.

UC IPM calls sticky traps the best way to detect and monitor cockroaches. Place them where walls meet the floor, behind large appliances and inside cabinets, then check which traps catch the most. Look near those spots for dark fecal specks, shed skins, egg cases and dead insects. The trapped insects are also the easiest thing to identify: photograph one on the trap and the app identifies it, then compare it with the four species above.

Research and drafting for this page used AI assistance. Every figure, date and quotation was then checked line by line against the sources listed at the bottom of the page, each of which was opened while writing. Nothing here is a diagnosis. If a bite, sting or contact with an insect is followed by trouble breathing, swelling of the face or throat, spreading redness, fever or any symptom that worries you, get medical care; in the United States Poison Help (1-800-222-1222) is free and open 24 hours a day.